Introduction. Mango producers of two important growing areas of the states of Guerrero and Michoacán, Mexico, reported extensive damage in mango trees caused by an abundant mycelial growth covering most diseased panicles of mango trees cv. Haden. Materials and methods. The fungus was isolated from panicles of mango. Pathogenicity was evaluated in the orchard by inoculating 20 inflorescences protected by cellophane paper bags. In vitro characterization was evaluated on monosporic cultures; conidial morphology and rate of growth were determined. A molecular characterization by DNA extraction was carried out to identify the microorganism. Results. Cladosporium tenuissimum caused necrosis of flowers, pedicels and small fruits on inoculated mango panicles cv. Haden in the long coast of Guerrero and Michoacan States of Mexico. The affected organs were covered with grey cottony mycelia and an olivaceous, green to grey sporulation. In vitro, young colonies were also olive green and velvety, turning dark green to grey with a whitish outer margin. The growth rate of colonies was 0.46 cm·day–1. Conidia were subspherical, lime-shaped and fusiform, olivaceous in color with visible scars and denticle-like extensions. The mean size of conidia was (5.85 × 2.93) µm with variations of 3.2–23 µm × 1.98–5.47 µm. The molecular characteristics rendered C. tenuissimum after identification. Symptoms of inoculated or naturally infected tree organs were similar. A diagrammatic scale was developed for the evaluation of disease severity, which varied from 69% to 100% in infected panicles. The organs were susceptible from blooming to fruit set. Discussion. Further research is proposed to evaluate the geographical distribution of C. tenuissimum in the production areas of mango with the concomitant evaluations of strategies of control.

La phaeoramulariose des agrumes au Cameroun due à Phaeoramularia angolensis : expression parasitaire à différentes altitudes.Résumé – Introduction. La phaeoramulariose ou cercosporiose des agrumes due à Phaeoramularia angolensis (De Carvalho & Mendes) P.M. Kirk constitue une sérieuse contrainte de production en Afrique tropicale. L'expression parasitaire peut varier de façon notable d'une localité à l'autre. Matériel et méthodes. L'évolution de la maladie sur de jeunes plants de pomelo Marsh inoculés à l'aide d'une suspension conidienne a été étudiée sur huit sites d'altitudes différentes (80 m à 1250 m). Les données de température (T) et d'humidité relative (HR) maximales, moyennes et minimales ont été relevées sur les sites durant la période d'observation. Résultats et discussion. L'incidence de la maladie a varié de façon croissante en fonction de l'altitude. Sur les huit sites étudiés, celui de Nyombé à 80 m d'altitude (Tmoy > 25 $^{\circ}$C, Tmax > 30 $^{\circ}$C avec HRmoy < 80 %, HRmin < 60 %) s'est révélé très défavorable à la maladie. En revanche, l'expression des symptômes a été complète sur les autres sites qui présentent des conditions climatiques plus fraîches et plus humides (Tmin < 20 $^{\circ}$C et HRmin > 60 %). Conclusion. Ces résultats constituent les premières données de caractérisation des zones à risque d'invasion par P. angolensis. Ces résultats joints à d'autres travaux ultérieurs impliquant différents contextes écologiques permettront d'établir une cartographie du risque épidémique.

Introduction. Beginning in 1994, vanilla vines grown under shade houses in Reunion Island have developed disorders mainly due to the cymbidium mosaic potexvirus (CymV) and potyviruses. To reduce damage and avoid viral epidemics, we considered developing a vanilla nursery to supply farmers with virus-free plant material and to provide prophylactic advice. Accordingly, we determined the relationship between symptoms on vanilla leaves and viral diagnosis. We also determined the temporal and spatial distribution patterns of viral diseases. Materials and methods. Symptom assessment and serological tests were carried out on vanilla leaves (Vanilla fragrans) at various times. The relationship between symptoms and viral infection data was analyzed with Statistica software. Spatial distribution patterns of infected plants were generated with two-dimensional distance class analysis (2DClass). Results and discussion. Results showed that symptoms do not correlate well with serological diagnosis. Plants in all shade houses in the survey were infected mainly by CymV which spreads in the row according to cultural practices. Potyviruses could be transmitted both by insect vectors and mechanically, but for the latter case less efficiently than CymV. Conclusion. Results from this study can be used to develop control measures, including the production of healthy planting materials to manage plant disease epidemics. Further studies will involve the characterization of vanilla potyviruses so that reliable serological techniques and better molecular tools can be developed.